[Geojson] [Geowanking] [georss] simple 3D geocode for AR

Mon Aug 31 17:55:50 PDT 2009

Mike Liebhold wrote:
>  wondering if the location semantics in the URI could be as plain 
> language simple
also wondering, how much about rendering, viewing, and pov should be 
included in a uri.

probably none.

>
> ?
>
> Chris Goad wrote:
>> There is a substantive issue here to do with local coordinate 
>> systems.  When representing the features of a particular object it is 
>> sometimes useful to employ coordinates local to that object, and 
>> represent separately the position of the object in the world or 
>> relative to its parent in a heirarchy. Reasons: The  coordinates of 
>> features relative to the object may be known more accurately than 
>> global position of the object, and an AR device's relative position 
>> to the object might also be known with greater precision than its 
>> global position.  The object may not have a fixed position (eg AR on 
>> board a ship). The representation is more compact.
>>
>> 3d modeling formalisms support this (and full GML does too), but  
>> GeoRSS, GeoJSON, and KML do not. This is probably an argument for 
>> going to represententations  built for 3d in the first place for AR 
>> applications where local coordinates play a necessary role, but 
>> concievably there is a niche for our lightweight geo standards 
>> extended  by addition of a transformation node.
>>
>>
>> -- Chris
>>
>> ----- Original Message ----- From: "Christian Willmes" 
>> <c.willmes at uni-koeln.de>
>> To: "Mike Liebhold" <mnl at well.com>
>> Cc: "Ron Lake" <rlake at galdosinc.com>; "geojson" 
>> <geojson at lists.geojson.org>; <geowanking at geowanking.org>; "GeoRSS" 
>> <georss at lists.eogeo.org>
>> Sent: Friday, August 28, 2009 6:00 PM
>> Subject: Re: [Geowanking] [georss] [Geojson] simple 3D geocode for AR
>>
>>
>>> Hi,
>>>
>>> whats the problem here? Its simple coordiante transformation 
>>> stuff... or do I miss something?!
>>>
>>> The device gets the geocoordinates from the web, and computes those 
>>> using its own position and orientation to local camera coordinates....
>>>
>>> its that simple... I think. ;-)
>>>
>>> regards,
>>> Christian
>>>
>>> Mike Liebhold schrieb:
>>>> Ron Lake wrote:
>>>>> The most logical coordinate
>>>>> system for locating such items is a rectilinear coordinate system 
>>>>> (x-y-z
>>>>> frame) centered (origin) at the focal point of the camera.
>>>> What's the use case?
>>>>
>>>> In most cases, we probably can assume that the geo-annotations 
>>>> exist independent of the viewpoint; e.g. a viewer should be able to 
>>>> see the note attached to a restaurant from any perspective as they 
>>>> pass on a sidewalk, or drive by.
>>>>
>>>> In that case, we need absolute coordinates, not relative to the 
>>>> camera perspective.
>>>>
>>>> imho
>>>>
>>>> Mike
>>>>> Cheers
>>>>>
>>>>> Ron
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: Mike Liebhold [mailto:mnl at well.com] Sent: August 28, 2009 
>>>>> 2:05 PM
>>>>> To: Ron Lake
>>>>> Cc: Joshua Lieberman; geowanking at geowanking.org; geojson; GeoRSS
>>>>> Subject: Re: [georss] [Geojson] simple 3D geocode for AR
>>>>>
>>>>> Ron Lake wrote:
>>>>>> The use of geographic coordinates for [location of things in the 
>>>>>> field
>>>>> of view relative to the camera] likely does not. [ make sense]
>>>>>
>>>>> Ron,
>>>>>
>>>>> This is really counter intuitive, Can you explain what you mean?
>>>>>
>>>>> - Mike
>>>>>> -----Original Message-----
>>>>>> From: georss-bounces at lists.eogeo.org
>>>>>> [mailto:georss-bounces at lists.eogeo.org] On Behalf Of Joshua 
>>>>>> Lieberman
>>>>>> Sent: August 28, 2009 11:03 AM
>>>>>> To: geowanking at geowanking.org
>>>>>> Cc: geojson; GeoRSS
>>>>>> Subject: Re: [georss] [Geojson] simple 3D geocode for AR
>>>>>>
>>>>>> In both GeoRSS GML and GeoJSON, some explicit CRS needs to be 
>>>>>> specified to use 3-coordinate locations. The simplest one for 
>>>>>> GeoRSS seems to be epsg:4979 ( urn:ogc:def:crs:EPSG:4979 ). It 
>>>>>> would need a slight modification to support the GeoJSON long-lat 
>>>>>> encoding. Otherwise use GeoRSS Simple and the elev property.
>>>>>>
>>>>>> e.g.
>>>>>>
>>>>>> <georss:elev>346</georss:elev>
>>>>>> <georss:point>42.3234 -173.234134</georss:point>
>>>>>>
>>>>>> Well-known text description of 4979
>>>>>> (http://spatialreference.org/ref/epsg/4979/ )
>>>>>> GEOGCS["WGS 84", DATUM["World Geodetic System 1984", SPHEROID["WGS
>>>>> 84",
>>>>>> 6378137.0,298.257223563, AUTHORITY["EPSG","7030"]], 
>>>>>> AUTHORITY["EPSG","6326"]], PRIMEM["Greenwich",0.0, 
>>>>>> AUTHORITY["EPSG","8901"]], UNIT["degree",0.017453292519943295], 
>>>>>> AXIS["Geodetic latitude",NORTH], AXIS["Geodetic longitude",EAST], 
>>>>>> AXIS["Ellipsoidal height",UP], AUTHORITY["EPSG","4979"]]
>>>>>>
>>>>>> Josh
>>>>>>
>>>>>> On Aug 28, 2009, at 1:05 PM, Ron Lake wrote:
>>>>>>
>>>>>>> Sorry my example should have been
>>>>>>>
>>>>>>> <Point id = "P1" CRS = "http://www.blah.bla/standardCRS.xml">
>>>>>>> <coordinates>100 200 150</coordinates>
>>>>>>> </Point>
>>>>>>>
>>>>>>> But the argument is the same. Similar encodings can be made in JSON
>>>>>>> etc.
>>>>>>>
>>>>>>> R
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: georss-bounces at lists.eogeo.org
>>>>>>> [mailto:georss-bounces at lists.eogeo.org] On Behalf Of Andrew Turner
>>>>>>> Sent: August 28, 2009 9:57 AM
>>>>>>> To: geowanking at geowanking.org; GeoRSS; geojson
>>>>>>> Subject: Re: [georss] [Geojson] simple 3D geocode for AR
>>>>>>>
>>>>>>> Simplest?
>>>>>>>
>>>>>>> Just include a 3rd coordinate in GeoRSS-Simple point or GeoJSON
>>>>> point.
>>>>>>> No, this is not explicitly valid. But you see where that discussion
>>>>>>> gets us. Long windy roads of elusive semantic talk (arguably
>>>>> necessary
>>>>>>> in the lon term, but not simple or useable *now*, which is when
>>>>> people
>>>>>>> are building these tools).
>>>>>>>
>>>>>>> If we lose interest without achieving a near term concensus,
>>>>>>> developers will just do arbitrary, different solutions. Give them a
>>>>>>> simple answer now, even if it makes your 
>>>>>>> strict-validation-only-skin
>>>>>>> crawl just a little bit. :)
>>>>>>>
>>>>>>> So I say just do it, and we'll catch up with documenting it as uses
>>>>>>> emerge.
>>>>>>>
>>>>>>> Also, KML already supports 3D points.
>>>>>>>
>>>>>>> Andrew
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> (via mobile)
>>>>>>>
>>>>>>> On Aug 27, 2009, at 4:35 PM, Mike Liebhold <mnl at well.com> wrote:
>>>>>>>
>>>>>>>> A friend wrote me with a request for clarification on a topic 
>>>>>>>> we've
>>>>>>>> discussed many times here, but every time we've approached a
>>>>>>>> consensus the answer seems elusive.
>>>>>>>>
>>>>>>>> Many devleopers are starting to create applications for iPhones 
>>>>>>>> and
>>>>>>>> Android phones to view location specific data through the
>>>>>>>> viewfinder using the -imprecise- capabilities of the built in gps
>>>>>>>> and compass and applications platforms like Layar.
>>>>>>>>
>>>>>>>> The question:
>>>>>>>>
>>>>>>>> What is the -simplest- way to geocode a geoannotation in 3D using
>>>>>>>> geoRSS/Atom, geojson, KML ....?
>>>>>>>>
>>>>>>>> (Is there a practical reason why WGS '84 shouldn't be implicit, 
>>>>>>>> and
>>>>>>>> a CRS lookup NOT be required?)
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
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>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
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